Zac Efron Broke His Hand While Horsing Around Near Dave Franco's Crotch — VIDEO

The Neighbors press tour is just getting more and more interesting, thanks to its ever-game and very chiseled star. On Tuesday, we had the distinct opportunity of watching Zac Efron and Seth Rogen transform into teen girls on The Tonight Show, but now we have a very frank story about Zac Efron breaking his hand by touching balls on this, the second night of his back-to-back appearance on Jimmy Fallon's late night program. Apparently, Efron just loves to talk about balls. (Or, people love asking him about balls because they know he'll respond rather candidly).

So here's the gist: During a fight scene with his co-star Dave Franco, Efron broke his hand. How did he do that? Was it gruesome and physical? Were things nuts? Well, uh... they were nuts, yes, in the literal sense. Turns out, Efron broke his hand while in the region of Franco's testicles because apparently — Franco has "balls of steel."

Perhaps Efron and Franco were just playing that game that Efron described earlier during the Neighbors press tour — if you can recall, there's a little game the actors play backstage called "sack tapping," and it's exactly what it sounds like...

Anyway, you can watch the video below, and you can watch Neighbors when it hits the big screen on May 9. Obviously, be on the lookout for ball-grabbing and sack-tapping.

The Tonight Show Starring Jimmy Fallon on YouTube